Apparatus for germicidal treatment of air-borne bacteria



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H. w` ALEXANDER 'APBARATUS FDR 'GERMICIDAL TREATMENT QF ATR-BORNE BACTERIA Filed Maron '13. 1942 June 6, 1944.

June, 1944. H. w, ALEXANDER APPAATUS FOR GERMICIDAL TREATMENT OF AIR-BORNE BACTERIA 2 SheebS-Sheet 2 Filed Marh 15, 1942 Izar- Patented June 6, 1944 'UNITED STATES APPARATUS non GERMCIDALTREATMENT or Aia-BORNEBACTERIA p Horace W. Alexander, Erie, Pa., assigner to American Sterilizer Company, Erie, Pa.

Application March 13, 1942, Serial No. 434,597

6 Claims.

This invention relates to improvements in a method lof and apparatus for germicidal treatment of air-borne bacteria.

`More particularly, the invention pertains toa method'oi` and apparatus for creating ultraviolet barriers in spaces such as operating rooms, class rooms and the like, whereby the air-borne bacteria circulated in the space by convection and movement of persons or objects therein is exposed to the lethal rays of ultraviolet radiation generators.

An object of the invention is to Vprovide a method of sterilizing a space, such as an operating roomfwith a plurality of overlapping, concentrated, lethal, ultraviolet radiations oi sufiicient potency to sterilize the air as it moves throught-he beams of lethal rays.

A still further object is to provide an'improved germioidal lamp wherein the ultraviolet radiations therefrom are controlled in such a manner that the beam of light therefrom is condensed into a substantially flat, fan-shaped form and with means attached to the lamp for varying the thickness and concentration of the beam.

A still further object includes a specific manner and method of sterilizing the air in an operating room with a plurality of overlapping, horizontal beams adjacent the top and underside of the operating table, whereby the danger of air-borne infection to the patient being operated on is vastly minimized.

Prior workers in the art have recognized broadly the problem of irradiating air with lethal light to minimize air-borne infection, as illustrated in the patent to Gordon M. Fair and William Firth Wells, No. 2,198,867, dated April 30, 1940, and the paper of Professor William Firthv Wells entitled Bactericidal Irradiation of Air, published in the Journal ofthe Franklin Institute, vol. 2,29, No. 3, March, 1940.

This invention contemplates an improvement over these basic studies of air sterilization and includes a novel method of room sterilization and an apparatus, including a lamp casing provided with a reflector-and control baule-therefor, whereby the ultraviolet rays of the lamp may be focused inA such a manner as to provide a true barrier. of lethal concentration,

In the drawings:

Fig-lis a diagrammatic, vertical sectionoi an operating room, showing the placement of the ultraviolet irradiators on the side walls thereof and the overlapping of beam barriers.

Fig. 2 is a diagrammatic top plan of an operating room, illustrating the manner in which lll the beams form an overlapping lethal barrier to air-'borne bacteria above and below the operating table. l

' Fig. 3 is a distribution curve Vof. the ultraviolet radiation of the germicidal lamp in several positions.

Fig. 4 is an end view of the improved lamp casing with the front'balile or hood in fully opened position.

Fig. 5 is' a front plan View of the irradiator lamp and reector therefor, showing its brackets and with the shutter 'or baffle in' lowered position.

Fig. 6 is a transverse, vertical section of the lamp and reflector, showing the irradiator tube mounting and baille in loweredA and partially raised position.

Fig. 7 is a diagrammatic View of thegermicidal lamp andindi'cating the manner in `which the rays' thereof are'reected in a fiat Vbeam when viewed from the side. Y n

It has now been established Athat ultraviolet radiation of germicidal wave length is an inherently unique agentfor the effective killingof air-borne bacteria. Ultraviolet energy isY substantially'un'absorbed by air and, therefore', without any effect thereon, andthe eiectiveness of the radiation is limited almostV solelyV byV the density of the' bacteria in the* air andv bythe distance the radiant energy can travel before being intercepted by a Wall or other absorbing medium.

While the' present concept includesthe method of producing horizontal, overlapping beams. of lethal "intensity ultraviolet radiation, produced by any'form of ultraviolet radiator and projectingapparatus, the `invention also specically includes an apparatus forcarrying out this method.

Referring to Figs. 4 to 7, inclusive, it will' be observed that the applicant `has invented anovel and" practical'form of projector consisting of an elongated casing I having rear, top, and bottom walls 3, 5, and l', respectively. The forward edgesV of the topV andv bottom' walls` are downturned, as denoted by numeralsV 9, tolie parallel to--the yrear -wall- 3; The-'extreme inner edges of the-'portions 9arefurtherinturned; as indicated by numerals II and I3, toform asupport'for'the top'ar'id'bottoml edges'of the horizontal, parabolic reflector I5. n Y

The casingv I` andw reector I5 are secured' to end members Il whichmay-be; castings or stampings having right angled portions VvI 9; 'I'hese end membersor braces ljl ract as end-walls for" the lamp-basing while giving reinforcement and rigidity thereto. Attached to the inner wall of the end angle members I'I is a conventional tube socket 2| whose tube supporting portions 23 extend outwardly at the ends of the reflector I5 for holding a suitable sized germicidal, ultraviolet irradiator 25. The casing also houses a reactor 21 of suitable capacity, and the irradiator 25 isconventionally wired therethrough to a source of potential for energizing the tube. Either integrally formed or suitably attached to the end frames I'I are outwardly projecting, apertured lugs 29 for supporting a horizontal tube or shaft 3| thereon, over which is fas,- tened a baille or shutter 33. 'This' baiile may be placed in any adjusted positionthrough the medium of end wing nuts 35 whereby the lower rays of the tube 25 may be controlled. Fig. 6 shows the baille 33 in fully opened position and in dotted lines shows it in partially raised position, In forming the curvedreflector I5, it is Vso constructed that the rays A and C are directed in substantially parallel paths so that the beam of ultraviolet irradiations has considerable length but comparatively little vertical spread, and, consequently, the reflector contour prevents little reflecting radiation in a direction below the horizontal. Such stray rays are prevented by intercepting the direct irradiation of the tube in a direction below the horizontal meansv of the Lbale 33.

The distribution of ultraviolet radiation in microwatts per square centimeter at one meter distance is plotted on the chart illustrated in Fig. 3. It will thus be appreciated that thisv type of reflector will give a long, ilat, horizontal, fanshaped beam of ultraviolet radiationsrof lethal concentration. y

In Figs. 1 and 2, there is disclosed the pre- 1 vferred manner of sterilizing theL air in an operating room, whereby two distinct lethal barriers are formed land thereby substantially eliminate the danger of air-borne infection to a patient being operated on. In these drawings, |00 denotes an operating room on whose walls are placed a plurality of ultraviolet irradiators, as Y heretofore described. In placing the irradiators, it is preferable to position a lower series IDI on the walls at a height which will notrise above vthe operating table Iil2 but will strike the lower extremitiesof the operating team |03. A second series of irradiators |04 is positioned slightly above the eye level of the operating team, and thus, there is 'created two horizontal, substanj tially flat beamed, overlapping, irradiated Vareas forming Aa lethal barrier to air-borne infections,.

it will be appreciatedthat if the room is comparatively small, a horizontal barrier may be created by the use of Va germicidal lamp placed on the wall of a room slightly above the normal eye level. so that the flat beam of lightis projected across kthe room to Vthe opposite wall thereof.

CII

With ultraviolet irradiating tubes of the type now being made and of 30 watts intensity, it is possible, with the use of a lamp housing, as before described, to project a lethal barrier upward to 35 feet in length.

The light ray projector, forming a part of this invention, may also find application over doorways to hospital wards, sick rooms, school rooms and the like and may be used to form a vertical barrier between cubicles or between adjacent beds in a ward.

What I claim is:

l. An ultraviolet projector for use in projecting a substantially flat horizontal fan shaped beam of ultraviolet radiation across a space including an elongated, horizontal casing having an open front wall; a trough-like, unsymmetrical, parabolic reflector mounted in said open front wall; anda tubular ultraviolet generator positioned adjacent and in spaced relation to the point of inflection of said unsymmetrical reflector. Y

2. An ultraviolet projector of the type defined in claim 1, wherein a horizontal baille is secured in pivoted, adjustable position at the lower portion of said front wall whereby the lower ultraviolet rays of said projector may be intercepted.

3. An ultraviolet projector including a troughlike reilectorvwhose vertical section is of generally parabolic shape but of unsymmetrical contour, and an elongated, ultraviolet generator positioned outwardly of and across the point of inflection of said generally parabolic reector, the contour of said reflector being such that the intensity of the beam of said generator when energized and measured at a point in the focal plane of projection at la given distance from said generator is at least twice the intensity of said beam at an angle of 20 above and below said focal plane.

4. An ultraviolet projector including an elongated, unsymnietrical, generally parabolic reflector and an ultraviolet generator tube positioned Voutwardly from and extending along the point of inflection of said reflector, the contour of said reflector being such as to project thev upper, central and lower rays of the said tube in substantially parallel paths in a substantially flat beam of considerable length and comparatively little vertical spread.

5. A germicidal lamp adapted to be mounted on a vertical surface and project a substantially flat horizontal beam of lethal intensity at a right angle thereto comprising the combination of a horizontal, box-like casing having a substantially open front wall; a generally parabolic, troughlike, unsymmetrical reflector secured within the casing and lattached to the longitudinal edges of the said front wall; a lamp socket comprising twoY spaced apart portions secured to the inner rear wall of the casing at the opposite ends thereof behind the said reflector and extending out wardly parallel to the end walls of the casing and a tube-like, ultraviolet irradiation generato mounted in said spaced socket portions whereby said tube lies adjacent to but spaced from the point of inflection of said unsymmetrical reilector.

Y HORACE w. 

